Single croaks are uttered at any time of the day. The embrace, the male digging its fists into the armpits of the female, often takes place on land, near the edge of the water, to which they resort in the night for spawning. The egg-strings are slung around water-plants, unless the water is a mere puddle, and are much shorter than those of _B. viridis_, measuring only 5 to 6 feet, and containing altogether 3000 to 4000 eggs. The larvae, when hatched, are very small, imperfect, and blackish; the external gills last a very short time. The young tadpoles live on mud, subsisting on diatoms and low Algae; they are the smallest tadpoles of all the European kinds, scarcely reaching more than one inch in length, and they metamorphose quickly, the baby-toads leaving the water and running about in less than six weeks, when they are only 10 mm., scarcely three-eighths of an inch, in length. By the end of their second summer they are still only three-quarters of an inch long, and they do not reach maturity until the fourth or fifth year, with a size of 1½ to 2 inches; still smaller young males become mature several years before they are full grown. Natterjacks stand captivity well and become very tame. When discovered, they first do their best to run away, instead of hiding or squatting down, and when caught they become covered with a slightly foamy lather, the exudation of their glands, which has a peculiar smell, reminding some people of gunpowder, others of india-rubber. They are not very particular as to food, all sorts of insects and earthworms being taken. Natterjacks are great climbers and diggers. Many of mine have established themselves in the peat with which the walls of the greenhouse are covered, where they have dug out, or enlarged, holes in which they pass the daytime, just peeping out with their bright eyes; others sit high up, always in dry places, and bask. In the evening they descend, hunting about on the ground, and occasionally they go into the water, whereupon they become quite flaccid and soft. When taken up and held between two fingers, being slightly pressed under the armpits, both sexes utter little jerky notes, as–by the way–most toads and frogs do under similar conditions. In Cambridgeshire they frequent certain clay-pits surrounded {184}by high and steep walls of sand, the breeding places of large colonies of sand-martins. During the months of May and June they are found in the shallow water, running about on the mud, sometimes swimming, in which they are not very proficient, and rarely diving. But they spend most of the time on land. Early in October they climb up and enter the holes of the sand-martins, or they dig large, deep burrows for hibernation, and the old males are the first to disappear.